Despite the vast ideological landscapes and political freedoms that set the United States apart from much of world, the presidential election has been, like so many other American elections of the past 150 years, ultimately a two-party contest.
While the names of an array of third-party candidates appear on ballots across the country on Tuesday, it’s been two decades since anyone not wedded to the Republican or Democratic parties has made anything more than a symbolic run for the White House or drawn more than a fraction of the vote. But in close elections, those fractions have often proved to be the difference.
Billionaire Ross Perot won 19 percent of the popular vote as an independent in 1992 and 8 percent in 1996 — the two strongest third-party performances since former Alabama Gov. George Wallace took five Deep South states in 1968 with his hard-line pro-segregation campaign.
John Anderson of Illinois grabbed 6 percent of the popular vote in 1980 as an independent, but, like Mr. Perot, failed to carry a single state.
This year’s third-party candidates were spread across the ideological spectrum — Rocky Anderson of the Justice Party, Virgil H. Goode Jr. of the Constitution Party, Gary E. Johnson of the Libertarian Party and Jill Stein of the Green Party — but political analysts said the race was stacked against them from the start.
“The two parties start out with the privilege of ballot access, government-run primaries and, more recently, government funding for their presidential campaigns,” said David Boaz, executive vice president of the libertarian Cato Institute.
Two-party control is so systemized that “an awful lot of Americans think that a third party is somehow un-American or unconstitutional,” said Mr. Boaz.
“It’s not true,” he added. “But I do think a lot of people think it.”
John Baughman, a political scientist at Bates College in Maine, where independent Angus King is seen as likely to pull off a rare U.S. Senate win Tuesday, says another factor has to do with the “psychology of voters.”
“Voters simply have a hard time thinking beyond the two parties they’re familiar with,” said Mr. Baughman. “A voter lacking much information about the candidates is often comfortable making a vote choice simply based on their party affiliation, but if it’s a candidate outside their party affiliation, making that choice is even harder.”
If a third-party candidate has a winning issue, meanwhile, it’s common for one of the major parties to co-opt it. Many think that was the case after Mr. Perot’s 1992 bid, when his focus on deficits helped propel President Clinton and Congress to several balanced-budget deals that put the government in the black.
Another factor favoring the two-party system is the U.S. constitutional structure, under which the president is chosen by the Electoral College, rather than by the party in power or an alliance of smaller parties — as is often the case in parliamentary democracies.
“We’ve got winner-take-all elections, as opposed to parliamentary elections like those in England or, say, Israel,” observed Ron Schmidt, who teaches political science at the University of Southern Maine. “The most logical thing to do is to pack as many supporters into one tent as you possibly can on Election Day, so just mathematically, two really big parties just makes more sense.”
Then, too, the major parties also guilt voters into avoiding votes for third parties.
Michael Kazin, a political historian at Georgetown University, said the two major parties tell “the electorate, ‘We understand you have grievances, but it would be much more practical for you to join into our party. If you do it with a third party, it will only hurt us.”